Abstract:  Greenhouse gas emissions have caused severe global climate change, and countries around the world are taking measures to mitigate the greenhouse effect caused by carbon emissions. Carbon dioxide capture and storage (CCS) is emerging as a large-scale greenhouse gas reduction technology and is gradually becoming one of the most important means of mitigating the greenhouse effect. There are a series of issues in the implementation of this technology, among which the geomechanical problems caused by injection and storage cannot be ignored. This paper reviews the impacts and risks caused by geomechanical problems due to injection and storage in CCS. The results indicate that CO2 injection triggers pore pressure variations, thermal stress, and coupling effect of chemistry and mechanics, leading to reduced reservoir rock strength, intensified deformation, and subsequent surface deformation. InSAR technology effectively monitors surface deformation, while site-specific microseismic monitoring reveals a direct correlation between injection rates and seismic activity. Controlling injection rates and pressures can significantly reduce the probability of caprock fracturing and fault reactivation. Furthermore, numerical simulation serves as a primary tool for assessing geomechanical risks at storage sites. Simulations demonstrate that selecting caprock with low-permeability and low-reactivity lithology minimizes leakage risks, and comprehensive evaluation of fault stress states is essential to avoid high-activity fault zones.

Key words: CO2 geological storage, site monitoring, numerical simulation, rock mechanics, thermal effect